As long as Central Texans are praying for more rain to refill their reservoirs, they also might want to pray for less soil to flow with it.

Sedimentation — a fancy word for dirt washing into waterways and settling on the bottom of riverbeds and lakes — slowly eats into the amount of water that reservoirs can hold.

Some Texas lakes — including Lake Buchanan, one of the key reservoirs for Central Texas — have lost more than 10 percent of their capacity since they were built. Statewide, Texas reservoirs have lost millions of acre-feet of capacity.